The present invention relates to a refractory tube wall lining having a multiplicity of refractory tiles which are arranged next to and above one another.
Refractory tube wall linings are used, for example, to protect tube walls in furnaces of refuse incineration plants from corrosion caused by flue gases. In modern refuse incineration plants, the tube walls and tube wall linings are often exposed to temperatures of over 1000xc2x0 C. and, also if suitable materials are selected, undergo expansion and contraction owing to the considerable differences in temperature between the individual operating states. The temperature differences are generally greater at the tube wall linings than at the tube walls, and this has to be taken into account when selecting the material and/or design of the tube wall linings, so that the tube wall linings are not destroyed by greater expansions and contractions than the tube walls.
The selection of a suitable material for the tube wall lining enables the tube wall lining to be adapted to the tube wall for each operating state. For tube walls made from steel, SiC tube wall linings have proven suitable, in which linings the SiC content may vary considerably. In practice, SiC mixtures or SiC tiles with an SiC content of 30%-90% are used.
Various refractory tube wall linings are known which comprise a multiplicity of refractory ceramic SiC tiles which are arranged next to and above one another and are each attached by means of at least one tile holder to the tube wall to be protected. The SiC content of the ceramic tiles varies; however, the use of so-called SiC 90 tiles, i.e. tiles with an SiC content of approx. 90%, is widespread.
In the tube wall tile system JUSYS RWS 4.2 produced by Jxc3xcnger+Grxc3xa4ter GmbH, Schwandorf, Germany, each tile is, firstly, supported and retained in the wall direction by a pin which is welded to the tube wall and, secondly, is bonded to the tube wall by means of an SiC mortar.
In the tube wall tile system Carborundum produced by Saint-Gobain Industriekeramik GmbH, Cologne, Germany, each tile is hung from a pin-like tile holder which runs obliquely upward from the tube wall.
EP-A-0 656 508 has disclosed a refractory tube wall lining in which the tiles are attached to webs of the tube wall between the tubes by means of screws. These screws are in this case responsible for both a supporting function and a holding function.
One problem which arises with these tile systems is the susceptibility of the tube wall lining to damage if the refuse incineration plant is run up too quickly, since tube wall lining and tube wall are heated at different rates. Since the freedom of an individual tile to move is limited by the tile holder and the adjoining tiles, the more rapid expansion of the tile compared to that of the tube wall in the event of the plant being run up too quickly cannot be compensated for, and the tile and/or adjacent tiles is or are broken off or detached.
DE-U-89 08 821 has described a tube wall lining in which lining bricks are supported and held by brackets and holders, respectively. The brackets and holders are arranged directly on the tubes, which in certain countries requires inspection by an expert.
U.S. Pat. No. 3,850,146 has disclosed a refractory tube wall lining in which a multiplicity of refractory tiles arranged next to and above one another are held on a tube wall with tubes which are connected by webs by means of tile holders, the tile holders not having any supporting function. A plurality of tiles arranged above one another are supported by brackets which are welded to the tubes. The tile holders are attached on the tube wall side by means of the brackets.
The fact that the tile holders do not have any supporting function means that they can hold the tiles on the tube wall in a vertically displaceable manner. However, a problem of this tube wall lining is that the brackets have to be welded to the pipes, i.e. to the pressure bodies. In many countries, welds on the pressure body have to be checked by a recognized expert or a designated authority. Also subsequent changes are relatively complex for this reason.
In view of the drawbacks of the known tube wall tile systems, the present invention is based on the object of providing a refractory tube wall lining having a multiplicity of refractory tiles which are arranged next to and above one another and where different expansions and contractions of the refractory tiles and the lined tube wall can be absorbed in both the vertical and the horizontal direction without damage to the tube wall lining and which can be fitted without welding on the tubes.
This object is achieved by means of the refractory tube wall lining according to the present invention. An alternative embodiment of the present invention includes a wall which has been provided with a refractory lining according to the present invention. Another embodiment relates to a method for refractory lining of a tube wall. Additional alternative embodiments and modifications of the present invention are also disclosed.
The essence of the present invention consists in the fact that, in a refractory tube wall lining having a multiplicity of refractory tiles which are arranged next to and above one another and each have at least one tile holder, which is or are intended to hold the tile on a tube wall which comprises tubes connected by webs, the tile holders having no supporting function, and the tiles being supported by at least one bracket which is independent of the tile holders, the tile holders and the bracket or brackets are designed to be attached to the webs of the tube wall.
The fact that the tube wall lining is attached to the webs and not to the tubes means that the pressure body is not impaired. Therefore, there is no need for checks by a recognized expert or a designated authority. A further advantage is that the tile holders and the brackets are cooled through their connection to the webs. Moreover, since the tiles are not rigidly attached to the tube wall, if the tiles are arranged suitably spaced apart, expansions and contractions of the tiles can be absorbed through displacement in the vertical and horizontal directions.
In a preferred embodiment, a plurality of tiles which are arranged above one another are supported, directly or via the tile or tiles arranged below them, by a single bracket which, when the tube wall lining is mounted on a tube wall, is attached, by welding to the tube wall. The tiles supported by the bracket can then expand and move upward. The tile mobility which is increased in this way compared to the prior art enables greater expansions and contractions of the tube wall lining to be absorbed without damage than is the case with known tube wall tile systems.